ENH: Simplify JSON & Dictionary parsing logic

[rmhowe425]

There are a few places in the code where multi-conditional look-ahead logic is used to parse JSON / dictionary pairs. This logic could be simplified to improve overall readability throughout the code.

A few examples are listed below:

• Line 125 & 127 in get_screenshot() in shodan.helpers.py

• Line 96 and below in shodan.cli.host.py

• Example briefly discussed in Added SSH Key & Fingerprint output to host command #201